Answer:
Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)
Step-by-step explanation:
a. The balanced chemical equation for the reaction between calcium metal and water to form aqueous calcium hydroxide and hydrogen gas is:
Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)
Note that the coefficients in the balanced equation indicate that one mole of calcium reacts with two moles of water to produce one mole of calcium hydroxide and one mole of hydrogen gas.
b. One chemical evidence for this reaction is the observation of effervescence or the production of bubbles, which indicates the release of a gas (hydrogen) during the reaction.